Myxoma of the mandible

 Myxoma of the jaw bone is a peculiar and rare tumor. A case of myxoma of the mandible is described in a 38-year-old man. The plain X-ray showed multiple osteolytic destructive lesions in the molar root area. CT scans demonstrated osteolytic expansile lesions with mild enhancement of the solid portion of the mass. Histologically, the tumor is composed of plump stellate cells with abundant amorphous myxoid stroma.     

应用超声鉴别颈部交感及迷走神经鞘瘤

目的：研究颈交感、迷走神经鞘瘤的彩超诊断。材料和方法：收集２２例经临床、手术及病理确诊为颈交感１６例和迷走６例神经鞘瘤,均行彩超检查。结果：其中７例仅以肿瘤本身的声像图特征为诊断依据者,其术前作出神经鞘瘤诊断的４例,神经鞘瘤可疑、占位病变或淋巴结肿大各１例。无一例能确定神经来源。另１５例以动脉、颈内静脉与肿瘤三者间的相关位置作为彩超诊断的根据：发现１１例交感神经来源者,颈总（颈内）动脉移位并紧贴于肿瘤的前方至外方,颈内静脉移位于动脉之外后方,靠近动脉或与动脉相距３０°－９０°。４例迷走神经来源者,颈总（颈内）动脉移位于肿瘤之前内至内后方,颈内静脉与动脉相反方向移位于肿瘤外侧,动静脉相距１２０°～１８０°。结论：单纯肿瘤声像图难以区分颈神经鞘瘤,利用颈内动、静脉声像图可助诊断,其中颈内动、静脉－起被推移而相互位置不变或动、静脉相距０～９０°内时提示交感神经鞘瘤,动、静脉相距１２０°～１８０°时提示迷走神经鞘瘤。     

CT findings in osteoradionecrosis of the mandible

 CT scans of ten patients in whom the diagnosis of mandibular osteoradionecrosis was proven pathologically or by clinical follow-up were reviewed. All ten patients had bony abnormalities (cortical interruptions and loss of spongiosa trabeculation) on the symptomatic side. These were predominantly seen in the body of the mandible (premolar and molar region, eight patients), in some of these cases extending into the retromolar triangle (two patients) or mandibular angle (two patients). In the remaining two patients the abnormalities were in the ramus and angle. The two patients treated with iridium implantation showed localized lingual-sided cortical destruction. Three patients had a pathological fracture. The cortical destruction was buccal-sided in two and both buccal- and lingual-sided in three of the other five patients. Contralateral bony abnormalities were present in four patients. Soft tissue thickening on the symptomatic side was seen in nine patients. As the bony abnormalities in mandibular osteoradionecrosis are often associated with a soft tissue mass, CT differentiation from tumor recurrence can be diffficult. The association with cortical defects distant from the position of the original tumor (buccal surface or opposite side of mandible) should evoke the possibility of mandibular osteoradionecrosis.     

Malignant fibrous histiocytoma of the mandible

 We report a case of MFH of the mandible in a 16-year-old girl. The mandible is a rare location of MFH of bone, with only 21 cases described in the literature. Clinical, pathologic, and radiologic features are discussed, with special emphasis on the unusual pathologic and radiographic features.     

下颌骨骨折致下齿槽神经损伤影响因素分析

 目的调查下齿槽神经损伤在下颌骨骨折中的发生情况,分析可能的影响因素,为下颌骨骨折神经损伤早期诊断,早期治疗及对预后正确评估提供依据.方法对30例患者31处骨折情况进行调查随访,分析患者一般情况、骨折治疗方法、骨折移位、骨折类型及患侧下齿槽神经分布区的感觉功能检查等因素与下齿槽神经感觉异常之间的关系.结果下齿槽神经损伤的发生率与患者年龄(相关系数= -0.1554)、术前骨折移位(相关系数=-0.4948)及坚强内固定治疗(相关系数=-1.9888)有关.结论年龄大,下颌骨骨折移位严重和使用坚强内固定治疗,下齿槽神经损伤发生的可能性大、严重程度高.     

High-resolution dental magnetic resonance imaging of inferior alveolar nerve responses to the extraction of third molars

The objective of this study was to assess whether signal changes can be detected in the neurovascular bundle of the mandibular canal after the extraction of a third molar. We retrospectively analyzed MRI scans of 30 test subjects with healthy mandibles and 41 patients who had had a wisdom tooth extracted. Signal intensities were measured at particular sites in the neurovascular bundle, which were defined as regions of interest (ROI) in the sagittal T1-weighted images before and after intravenous administration of a paramagnetic contrast agent. On the basis of the signal intensity increases that were measured after contrast agent administration, we compared the signal increases obtained for the patients who had received surgical treatment with the results obtained for the population of test subjects with unremarkable mandibles (t-test, P<0.05). Compared with the healthy test subjects, patients who had received surgical treatment showed significantly higher signal intensity increases at two measurement sites, i.e., the second molar and the second premolar (P<0.05). We found no significant differences when the measurements were performed at the first molar (P=0.06), the third molar (P=0.47) and in the area of the ascending mandibular ramus (P=0.79). Compared with a population of healthy test subjects, patients who had their third molars surgically removed show higher signal intensity increases in the neurovascular bundle after intravenous contrast agent administration. The underlying cause may be the higher blood flow in the arteries and veins and the perineural plexus, which may give evidence of the pathophysiological mechanism of nerve damage in the narrow canal as a result of osteotomy.     

Luxatio erecta of the hip: a critical retrospective

 The term ”luxatio erecta” has been borrowed from the shoulder to identify rare traumatic hip dislocations in which there is inferior dislocation of the femoral head and inversion of the femoral shaft. A review of the literature is presented along with an additional illustrative case. The mechanism of injury, and the radiological and physical appearance of the patient, indicate that there are two subtypes of dislocation hitherto lumped together under the single term.     

Intraosseous neurilemmoma of the fibula

 We present a case of intraosseous neurilemmoma of the fibula in a 56-year-old woman. This case showed the typical radiographic appearance except for the presence of spotted calcifications that mimicked a cartilaginous tumor. Enhanced MR images revealed the heterogeneity of the tumor, which consisted of Antoni type A and B tissue.     

Assessment of tumour invasion into the mandible: the value of different imaging techniques

In oral carcinomas close to the mandible, tumour invasion of the mandible is important in selecting segmental or marginal resection. Imaging may play a role in assessing tumour invasion. This study compares the accuracy of panoramic X-ray, CT and MR imaging in assessing invasion of the mandible in 29 patients. At histopathology, 6 patients had mandible erosion, 12 had invasion and 11 had an intact mandible. Magnetic resonance imaging had the highest sensitivity (94 %), but a low specificity (73 %), with 3 of 11 intact mandibles interpreted as positive. Furthermore, MR often overestimated the extent of tumour invasion. On the other hand, CT and panoramic X-ray had a lower sensitivity (64 and 63 %, respectively) and a higher specificity (89 and 90 %, respectively). Computed tomography (using 5-mm sections) and panoramic X-ray had a similar accuracy, and negative findings do not exclude invasion. Magnetic resonance imaging was the most sensitive technique but had more false positives and frequently overestimated the extent of tumour invasion. Because none of the radiological techniques are accurate enough, clinical examination seems at present to remain the most important modality in deciding between segmental and marginal resection. Tumour invasion at CT or panoramic X-ray is a strong argument for a segmental resection. Received 23 December 1997; Revision received 12 March 1998; Accepted 20 March 1998     

Intraosseous lymphangiomas of the mandible

Central lymphangioma of bone is a rare entity which has not previously been reported in the English language literature as occurring in the mandible. Two cases of intraosseous lymphangioma of the mandible from the files of the Armed Forces Institute of Pathology are presented. While these lesions have clinical and radiographic features similar to hemangioma of bone, they do not pose the surgical hemorrhage control problems of hemangiomas. Solitary lymphangioma of bone may share similar histologic features with the disease entities systemic cystic angiomatosis and massive osteolysis. These latter two entities may cause complicated clinical management problems; curettage, however, is adequate therapy for solitary, localized lymphangioma of bone.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Air Force or the Department of Defense.     

下颌骨牙源性角化囊肿X线影像分析

目的：提高对下颌骨牙源性角化囊肿X线征象的认识。方法：回顾性分析经病理证实的60例下颌骨牙源性角化囊肿的X线资料。结果：下颌骨牙源性角化囊肿X线征象有：①下颌骨磨牙升好发区，17例（28．3％）；②牙根斜面状吸收多见，93个（71％）；③沿长轴生长40例（66．7％）；④X线分为4型：单房型18例（30％），多房型30例（50％），多发型8例（13．3％）及综合征型4例（6．7％）。结论：牙源性角化囊囊的牙根斜面状吸收和沿长轴生长是特征性的。     

Tuberculosis of the patella

 A rare case of tuberculosis of the patella is presented. Diagnostic features include an osteolytic lesion in the patella with flaky sequestrum, associated with typical clinical features. Treatment should be urgent and should include a regimen of surgical debridement along with four antitubercular drugs. Once the joint is involved, the end results become less satisfactory.     

Intraosseous malignant peripheral nerve sheath tumor in a patient with neurofibromatosis

Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon sarcomas that almost always arise in soft tissue. They can develop in pre-existing neurofibromas or schwannomas, de novo from peripheral nerves, or following radiation therapy. Primary intraosseous MPNST is rare and has been reported most frequently in the mandible. Of the reported cases involving the long bones, none has been associated with neurofibromatosis type 1 (NF-1). We report a case of MPNST arising in the femur in a patient with NF-1.     

Schwannomatosis of the sciatic nerve

A 52-year-old woman with schwannomatosis in the left sciatic nerve is presented. The patient had no stigmata of neurofibromatosis (NF) type 1 or 2. Cutaneous or spinal schwannomas were not detected. Magnetic resonance (MR) imaging of the sciatic nerve revealed more than 15 tumors along the course of the nerve. Histological examination revealed schwannomas consisting of Antoni A and B areas. Immunohistochemical study showed most cells reacting intensely for S-100 protein. The patient underwent conservative follow-up treatment due to the minimal symptoms. The relationship of the disease with NF-2 and plexiform schwannoma is discussed. Received: 5 September 2000 Revision requested: 5 October 2000 Revision received: 23 October 2000 Accepted: 26 October 2000     

Sarcoidosis of hands

 We present a case of sarcoidosis with soft tissue masses and associated phalangeal erosive changes. Sarcoidosis of the musculoskeletal system presenting as a soft tissue mass has been described previously but is rare. To our knowledge, the combination of soft tissue masses and phalangeal erosions has never been described.     

Extraskeletal mesenchymal chondrosarcoma of the rectus sheath

 Mesenchymal chondrosarcomas (MSCs) are a rare form of chondrosarcoma which usually arise in bone. Extraskeletal chondro-sarcomas constitute a minority (14–25%) of MSCs. We describe the imaging features of an extraskeletal mesenchymal chondrosarcoma that arose from the rectus abdominus muscle.     

Chondromyxoid fibroma of the sternum

 We report the fourth case of chondromyxoid fibroma of the sternum described in the literature. The clinical, radiographic, pathologic and treatment aspects of this case are presented, and the literature on chondromyxoid fibroma in this unusual location is reviewed.     

Gray-scale ultrasonography in the evaluation of bone callus in distraction osteogenesis of the mandible: initial findings

The accuracy of panoramic radiography (RX) and ultrasound (US) in the evaluation of both the length of the osteotomic gap and the quality of new bone formation in patients undergoing mandibular distraction osteogenesis (DO) was assessed, verifying the results against intraoperative and histologic findings. In 31 patients, three RX and three US examinations were performed after DO. RX and US findings were each independently compared, at the time of distractor removal, to the direct intraoperative measurement of the osteotomic gap and to the histologic evaluation of the maturity of a resected specimen. No significant differences (P > 0.1) resulted at any step between RX (average length: 18.19 mm) and US (18.29 mm) measurement of the osteotomic gap. In the assessment of the callus maturity the difference between RX and US (P < 0.001) was statistically significant: at the final control the maturity score averaged 0.612 at RX, 3 at US and 3 at histology. RX and US are equally reliable in the measurement of the osteotomic gap, while US is much more accurate than RX in the evaluation of the callus maturity. US-based follow-up might allow a safe shortening of the fixation period.